Hubble image archive

Gravitational Lens Helps Hubble and Keck Discover Galaxy Building Block

This NASA Hubble Space Telescope image shows a very small, faint galaxy 'building block' newly discovered by a unique collaboration between ground- and space-based telescopes. Hubble and the 10-meter Keck Telescopes in Hawaii joined forces, using a galaxy cluster which acts as gr...

Date
Jan 1, 2001
Mission
Hubble Space Telescope
Archive ID
hubblesite-images-2001-32-1114-image
By

This NASA Hubble Space Telescope image shows a very small, faint galaxy 'building block' newly discovered by a unique collaboration between ground- and space-based telescopes. Hubble and the 10-meter Keck Telescopes in Hawaii joined forces, using a galaxy cluster which acts as gravitational lens to detect what scientists believe is one of the smallest very distant objects ever found.

The galaxy cluster Abell 2218 was used by a team of European and American astronomers led by Richard Ellis (Caltech) in their systematic search for intrinsically faint distant star-forming systems. Without help from Abell 2218's exceptional magnifying power to make objects appear about 30 times brighter, the galaxy building block would have been undetectable.

In the image to the right, the object is seen distorted into two nearly identical, very red 'images' by the gravitational lens. The image pair represents the magnified result of a single background object gravitationally lensed by Abell 2218 and viewed at a distance of 13.4 billion light-years. The intriguing object contains only one million stars, far fewer than a mature galaxy, and scientists believe it is very young. Such young star-forming systems of low mass at early cosmic times are likely to be the objects from which present-day galaxies have formed.

In the image to the left, the full overview of the galaxy cluster Abell 2218 is seen. This image was taken by Hubble in 1999 at the completion of Hubble Servicing Mission 3A.

Credits

NASA, ESA, Richard Ellis (Caltech) and Jean-Paul Kneib (Observatoire Midi-Pyrenees, France);
Acknowledgment: NASA, A. Fruchter and the ERO Team (STScI and ST-ECF)

Image Details

About The Object
Object NameAbell 2218
Object DescriptionGravitational Lensing Galaxy Cluster
R.A. Position16h 35m 53.99s
Dec. Position66° 13' 0.0"
ConstellationDraco
DistanceThe lensing cluster of galaxies, (Abell 2218) is 600 million parsecs (2 billion light-years) away, along the same line of sight. The lensed galaxy is 4 billion parsecs (13 billion light-years) away.
About The Data
Data DescriptionPrincipal Astronomers: J.-P. Kneib (Observatoire Midi-Pyrenees, France), R. Ellis and M. Santos (Caltech) and K. Kuijken (Kapteyn Institute, The Netherlands)
InstrumentInset image: Keck I>Low Resolution Imaging Spectrograph, HST>WFPC2, and Keck II>Echelle Spectrograph and Imager
Exposure DatesInset image: April 23, 2001, Exposure Time: 0.6 hours (Keck I), January 11 - 12, 2000, Exposure Time: 3.3 hours (HST), and May 21, 2001, Exposure Time: 1.1 hours
FiltersInset image Low Resolution Imaging Spectrograph WFPC2: F814 W (I) Echelle Spectrograph and Imager Galaxy Cluster image F450W (Wide B), F606W (Wide V), and F814 W (I)

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